The present invention relates to an application device for applying a composite substance to a site.
A conventional application device is disclosed, for example, in DE-U1-9218949. In this application device, a support element is received in a case or sheath having side slots through which a fluid can penetrate, which serves to facilitate the wetting of the support element.
This conventional solution should operate to hinder the unobstructed leakage of fluid in the event, for example, that the application device is tipped. In this connection, sealing surfaces are provided between the slot and the application element.
A conventional solution of this type may serve a purpose in connection with the field of cosmetic products. In connection with the field of dental products, however, a precise application of an application element is important. Even if relatively small holes in the slot are provided as disclosed in DE-U1-9218949, which, in accordance with that disclosure, should exercise a certain protective effect, it is not foreclosed that fluid penetrates inadvertently and that the application element is already in a mixed condition prior to the actual wetting operation in which the application element is wetted with the reaction substance.
Numerous other application apparatus are known. For example, an application element has been proposed which is maintained in a submerged condition in a fluid and the pushing down of the receptacle holding the fluid permits an inflow of an additional fluid in the manner of an overflow, in order to thereby place in readiness the mixture which is to be applied. Unfortunately, this solution requires to be sure two separate sealing systems, so that a not inconsiderable effort is required. The need for a multitude of sealing bands necessarily involves a correspondingly large susceptibility to unhygienic conditions and positional instability.
It is further known, in this connection, to provide a membrane disposed between two chambers which each receive a fluid, with the membrane being destroyed in a targeted manner by a sharpened pin which is actuated to destroy the membrane by compression of an inner chamber. This solution requires a particular configuration of the sharp pin, if it is to be reliably ensured that a collision between the sharpened pin and the application element is prevented.
It is further known to mix reaction capable substances such as, for example, a composite for teeth filling, with a base element having a peroxide coating or, respectively, to mix the reaction capable substance with the composite with a peroxide coated spatula. This type of mixing has the disadvantage that a homogeneous mixing with the substantially viscous composite material must be completely utilized.
It is further known, from DE-PS 4315920, to provide a mixing capsule for dental material, the mixing capsule having a cylinder which is provided with a plunger in order to make possible a targeted dispensing of the activated material. This solution permits up to two fluid components and a powder component to be maintained in spaced apart relationship in readiness and to mix, as necessary, that is, immediately before the application, the components with one another.
However, the application of more than three components, as well as the application of a plurality of components one after the other, on the site which is to be treated is not possible with the heretofore known application apparatus.
A further problem with single dose units is the fact that very different amounts of the required components are needed in accordance with the respective size of the site to be handled. In accordance with the concept of single dose units, the unused portion, which can comprise, indeed, up to 90% of the total amount, is then thrown away. From the prospective of cost effectiveness, this is not desired and dentists tend to use the component in bundles and to mix the components in such a manner. Such self-mixing, however, requires a corresponding degree of experience to ensure, on the one hand, a good mixing of the components and, on the other hand, to place in readiness the application amounts in their proper relationship to one another.